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1  Using Arduino / Project Guidance / MPPT delaying issues on: April 15, 2013, 06:27:04 pm
I am trying to make a MPPT. I am taking in two voltage measurements. One of the voltage measurements comes from a voltage divider. The other voltage measurement is a voltage output from a current sensor. I am multiplying these voltages to get a power measurement. The first power measurement is coming out fine, but when I try to delay the second power measurement and compare them it comes out the same as the first power measurement. This should not be because happening because I am changing the voltage that it is sensing with my power supply. I want to measure two power measurements and compare them to get my dp/dv and then use my change in power to adjust my duty cycle.  I also am not sure that I am adjusting my duty cycle right because my change in power is always zero. I am hoping by the end of tonight to be able to check my duty cycle on this ocilloscope.
2  Using Arduino / Project Guidance / Re: 125k frequency sq wave on the mega2560 on: March 20, 2013, 05:24:45 pm
Thanks for the quick replies. I really appreciate it. I have now been able to find a pwm library and have a working square wave that I can adjust the duty cycle from 0 to 50 percent on. This is exactly what I need. Now I just need to build my sensing circuit and see if I can get the mppt to work with a little peturb and observe. Again you all rock, Thanks.
3  Using Arduino / Project Guidance / output on display EMG on: March 20, 2013, 03:20:40 pm
i need a code that simply displays the output of a functional generator.  For instance, if the amplitude is 2 volts, i would like to see a sinusoidal output of 2 volts pk-pk on the computer.  I have this emg device that displays emg muscle output on a an osciloscope, but would like to see the same oscilscope output on the computer.  as muscle twitches so shall the output of the display change between frequency from 40 to 400 hz smiley-razz.
4  Using Arduino / Project Guidance / 125k frequency sq wave on the mega2560 on: March 20, 2013, 03:00:49 pm
I am trying to use the arduino mega2560 to drive a h-bridge at a 125kHz frequency. To do this I need two square wave outputs that are at 125kHz. Is this frequency achievable because I have tried looking on line to see examples, but even the examples I have seen on line have not worked correctly for me. I am testing these straight from the arduino to an ocilloscope. I keep ending up with up with a square wave at around 79kHz with low resolution. I am also later going to put a mppt for a solar panel on the arduino and adjust the duty cycle of one of the square waves. That is later though right now I would really just like to figure out how to adjust the frequency. Does all of this sound possible, and if so is there some example of code out there that will adjust my frequency correctly. Thanks in advance for any advice.
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